Any vector field may be decomposed, in a unique way, into an irrotational and a rotational part, if appropriate boundary conditions are imposed to the scalar and vector potentials introduced by the above decomposition. In the present work, the transformation is applied to the mass flux vector, in order to calculate two-dimensional, steady, rotational, transonic flows in arbitrarily shaped ducts and plane cascades. The whole procedure is discussed from an analytical and a numerical point of view, while finite difference-finite volume schemes are used to derive numerical results.
Nomenclaturea { = inlet flow angle a 2 = outlet flow angle c p -specific heat at constant pressure M = Mach number n = outward normal to the boundary vector p = pressure R g = universal gas constant S -entropy T = temperature (u,v) = velocity components in (x,y) coordinate system V = velocity vector x,y .= coordinates in physical space y = isentropic exponent £,ri = coordinates in computational space p = density O = scalar potential *p = vector potential co = relaxation factor Q = vorticity Subscripts and Superscripts t = total thermodynamic quantities n = normal to the boundary component n = number of current iteration (Note: Subscripting a variable with any of the coordinates indicates partial differentiation, whereas indices ij indicate the node point.)